A micro-electro-mechanical systems (MEMS) microphone, which converts a sound signal into an electrical signal, may be manufactured by a semiconductor batch process. Since the MEMS microphone has excellent sensitivity, low performance deviation for each product, and strong humidity resistance and heat resistance compared with an electret condenser microphone (ECM) which is currently mostly used in vehicles, and may be manufactured in a small-sized type, the ECM has recently been increasingly replaced with the MEMS microphone.
Unlike a microphone used in a mobile phone, since the microphone used in the vehicle is disposed far from a sound source and is positioned in a harsh environment in which noises variously occur in a vehicle, it is required to develop a microphone that is performs well in a noisy environment inside the vehicle.
For this purpose, by arranging MEMS microphones in an array type and applying a beam forming technique thereto, a directional scheme of receiving only a sound from a desired direction may be used. However, as such a directional array MEMS microphone includes two or more digital MEMS microphones and a digital signal processing (DSP) chip, the manufacturing cost thereof is excessive, thus it is difficult to apply it to the vehicle.
Accordingly, it is required to develop a directional MEMS microphone that exists as a single element.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.